Borrelia (Borrelia burgdorferi), IgG antibodies
Why this test?
To determine whether a person has been infected with Borrelia burgdorferi bacteria. This allows you to confirm the diagnosis of tick-borne borreliosis. To monitor the effectiveness of treatment.
In what cases is it prescribed?
The test is prescribed for symptoms of tick-borne borreliosis.
In the early stages, there may be: erythema migrans, fever, chills, headache, fast fatigue, nausea. Additional evidence for the analysis is a tick bite (a few days or weeks before the first symptoms appear).
In some cases, it is even possible to test the tick itself for B. burgdorferi. If the result is positive (that is, the tick is a carrier of borreliosis), then the bitten person should take the test himself (it will be possible to detect antibodies after a few weeks).
Symptoms of borreliosis in later stages: periodic pain in the joints, bones and muscles, meningitis, facial nerve palsy, numbness of the limbs, memory disorders damage to the eyes and heart (in some cases).
In addition, the analysis is prescribed if necessary to ensure the success of the treatment.
This test detects antibodies to Borrelia burgdorferi, which are produced by the body in response to infection. Their presence means that a person was infected with these bacteria.
B. burgdorferi belongs to the group of spirochetes and causes tick-borne borreliosis (Lyme disease). A person becomes infected if they are bitten by a tick that has itself been infected with B. burgdorferi. Ixodes ticks, carriers of borreliosis, are very common, in the temperate zone of the Northern Hemisphere they are found everywhere.
Most often, people are infected during the period of activity of ticks - in spring and summer. The incubation period of borreliosis is several weeks. In the early stages, the following symptoms may be observed: fatigue, chills, headache.
Also, with borreliosis, a characteristic rash sometimes occurs - erythema migrans (ring-shaped reddening of the skin, which gradually expands). If the disease is not treated, serious problems are possible: joint pain, meningitis, numbness of the limbs, paralysis of the facial nerve, memory disorders and (in some cases) damage to the eyes and heart. Treatment of the disease, as a rule, is effective.
Upon infection, human lymphocytes begin to produce antibodies - special proteins (immunoglobulins) that must neutralize the bacteria. Immunoglobulins M (IgM) are the first to appear in the blood, but gradually their concentration decreases.
After some time, antibodies of another type appear - immunoglobulin G (IgG).They can be detected a few weeks after infection, and they reach their maximum level after 4-6 months. Thus, IgM antibodies indicate a recent infection, while immunoglobulin G is suitable for a later diagnosis. The number of antibodies is expressed as a titer. The titer is the maximum dilution of the solution at which antibodies are still detected in it. For example, a titer of 1:16 means that if the blood serum is diluted 16 times, antibodies can still be detected in it (and if diluted more, antibodies are no longer detected).
The titer is called high (for example, 1: 612) or low (for example, 1: 4), its specific value depends on the sensitivity of the method. A high titer is more likely to indicate current disease (rather than past disease).
It is important to remember that the titer is NOT proportional to the severity of the disease, because it is not about the number of bacteria, but about the number of antibodies against them. Detection of antibodies is recommended to be carried out in two stages. The first step is to measure the titer of IgM and IgG antibodies. If the result is positive or ambiguous, then you need to pass another analysis - immunoblot.